The present invention relates to a dental chair or a chair for dental treatment.
A dental chair or a chair for dental treatment is generally provided with three basic operational functions: seat-elevating, seat-tilting and seatback-reclining functions. Among the means for driving the mechanisms which perform the above functions, there is the so-called manual system in which a manual switch provided in each power circuit is kept depressed to operate each mechanism thereby changing the positions of the seat and seat-back according to the patient's constitution or part to be treated. With this system, however, it is necessary to return the seat proper to its original position every time when the patient gargles; therefore, the operation to move the seat proper from the original position to the treating position and vice versa must be repeatedly performed during treatment by operating the manual switch, and in addition the manual switch must be kept depressed until the seat proper reaches a desired position. Thus the use of this manual system results in a very low operational efficiency.
As an improved version of the above system, therefore, there is provided a system which once puts the seat and seat-back at positions suitable for the patient's constitution and part to be treated, and stores these positions in a memory so that the seat proper may be placed at the predetermined position simply by momentarily depressing an "AUTO" button. In the system of this type, the setting part such as a control dial or the like provided externally of the seat proper is set to a predetermined scale value and then the power circuit is energizd to operate for a period corresponding to the scale value set by the above setting part thereby bringing the seat proper to a predetermined position, which is then memorized in a memory if it is suitable for treatment. Thus the above system has an advantage in that it can preset the position of the seat proper; however, it has a disadvantage in that it cannot confirm the position of the seat proper until the seat proper is actually moved, because the seat proper is not moved when the scale value is being preset by the setting part; in other words, the setting part can preset only an approximate value and therefore must perform setting operation repeatedly until the seat proper is brought to a position suitable for treatment.